1. Field of the Invention
The present invention relates to a droplet ejecting apparatus configured to eject a liquid such as ink for forming an image on a recording medium and to a technique of dealing with a curl of the recording medium, more particularly, to a technique of estimating or predicting a degree of the curl of the recording medium and/or a correction degree of the curl.
2. Discussion of Related Art
There is known an ink-jet printer, as one example of a droplet ejecting apparatus, configured to form an image on a recording medium by ejecting ink to the recording medium such as paper, cloth, or a film. The ink-jet printer often uses water-soluble ink. The water-soluble ink contains a large amount of water as a solvent. Due to the water component contained in the ink, there may be caused a curl of the recording medium to which the ink has been attached by image formation. The degree and the state of the curl vary depending upon conditions of the attached ink. In general, when a difference in the amount of the water component becomes large between a front surface and a back surface of the recording medium due to the attachment of the ink to the recording medium, the curl is likely to occur. Where the recording medium suffers from the curl, the recording medium is not stacked in good order when discharged, causing a trouble that the recording medium is bent or placed out of position. Accordingly; it is preferable to accurately estimate or predict the curl of the recording medium and to appropriately restrain the curl. In view of this, there is proposed a curl predicting method in which a liquid amount ejected by a droplet ejecting apparatus to each of regions defined on the recording medium is calculated and the curl state of the recording medium is predicted on the basis of a position of each region and the liquid amount ejected to the corresponding region.